The solid wood cladding products available can be primarily divided majorly into two types - Modified and Non-modified. By modified it is meant that the wood has been chemically altered in some manner to make it more suitable for outdoor use. Typically these are sustainable wood species being imported from the developed side of the world where such technologies have been commercially developed and are in use for some time now. Modifying wood used high temperatures (thermal modification) is one such technology that has become popular today. Thermal modification entails treating wood at temperatures above 200 degree Celsius typically 215 to 230 degrees which permanently alters wood chemistry making it more stable. It also seems to have a positive effect on the resistance to rot which is essentially a fungal mechanism. However termite resistance does not seem to improve and remains more or less the same as of the untreated base wood species. Additional treatments are needed to handle the termite threat. The most effective termite treatments penetrate deep into the wood, and are long-lasting in nature.
Acetylization and Furfurylation are other chemical modification techniques that are being used to modify wood and are available in the Indian market. Both techniques increase wood stability and rot resistance. The difference between the various technologies lies in changes in base wood colour, its structural strength, stability, resistance to insects and coating performance.
In the non-modified or natural timber category the available alternates are Ipe, a hardwood primarily originating from South America, Teak wood originating from Burma or other plantation forests around the world and others like Cumaru etc. With growing concerns about the source of timber and sustainability, the cost of these natural, old growth timbers is going up and availability reducing. Timbers which are 3rd party certified with traceable origins are more expensive and have a restricted availability. Though naturally durable, these species require skill full installation to achieve long term durability and beauty. With growing concerns world over on the depleting natural wood resources and sometimes illegitimate deforestation a preference towards modified, sustainable and certified wood species is seen as an emerging market trend.
To sum it up, when using wood outdoors, the various alternatives should be rated on aesthetics, durability and sustainability. The factors affecting are the wood colour, grain pattern, weathering performance (how the wood ages), resistance to termites, wood insects, fungal decay, coating performance, origin of wood and maintenance protocol. Used intelligently, wood on the facade can help make any building facade warm and inviting, providing an effective balance against other hard facade materials such as stone, glass, tiles etc.
